Cuecas Alba, Barrau M Julia, Gonzalez Juan M
Institute of Natural Resources and Agrobiology, Spanish National Council for Research, IRNAS-CSIC, Sevilla, Spain.
Front Microbiol. 2024 Feb 13;15:1355780. doi: 10.3389/fmicb.2024.1355780. eCollection 2024.
Species differentiation and the appearance of novel diversity on Earth is a major issue to understand the past and future of microbial evolution. Herein, we propose the analysis of a singular evolutive example, the case of microorganisms carrying out the process of anammox (anaerobic ammonium oxidation). Anammox represents a singular physiology active on Earth from ancient times and, at present, this group is still represented by a relatively limited number of species carrying out a specific metabolism within the Phylum Planctomycetota. The key enzyme on the anammox pathway is hydrazine dehydrogenase (HDH) which has been used as a model in this study. HDH and rRNA (16S subunit) phylogenies are in agreement suggesting a monophyletic origin. The diversity of this singular phylogenetic group is represented by a few enriched bacterial consortia awaiting to be cultured as monospecific taxa. The apparent evolution of the HDH genes in these anammox bacteria is highly related to the diversification of the anammox clades and their genomes as pointed by phylogenomics, their GC content and codon usage profile. This study represents a clear case where bacterial evolution presents a paralleled genome, gene and species diversification through time from a common ancestor; a scenario that most times is masked by a web-like phylogeny and the huge complexity within the prokaryotes. Besides, this contribution suggests that microbial evolution of the anammox bacteria has followed an ordered, vertical diversification through Earth history and will present a potentially similar speciation fate in the future.
物种分化以及地球上新多样性的出现是理解微生物进化的过去和未来的一个主要问题。在此，我们提出对一个独特的进化实例进行分析，即进行厌氧氨氧化过程的微生物的情况。厌氧氨氧化代表了一种自古以来就在地球上活跃的独特生理过程，目前，这一群体仍然由在浮霉菌门内进行特定代谢的相对有限数量的物种所代表。厌氧氨氧化途径中的关键酶是肼脱氢酶（HDH），在本研究中它被用作模型。HDH和rRNA（16S亚基）系统发育树一致，表明其单系起源。这个独特的系统发育群体的多样性由一些富集的细菌聚集体代表，它们有待作为单特异性分类单元进行培养。如系统发育基因组学、它们的GC含量和密码子使用谱所指出的，这些厌氧氨氧化细菌中HDH基因的明显进化与厌氧氨氧化分支及其基因组的多样化高度相关。这项研究代表了一个明确的案例，即细菌进化从一个共同祖先开始随着时间呈现出平行的基因组、基因和物种多样化；这种情况大多数时候被类似网状的系统发育和原核生物内部的巨大复杂性所掩盖。此外，这一贡献表明厌氧氨氧化细菌的微生物进化在地球历史中遵循了有序的垂直多样化，并且在未来可能会呈现出类似的物种形成命运。
